Comment 1 for bug 1001520

Comments:
[r=jcsackett][bug=992692][no-qa] clear out any existing log handlers
       at the start of each test case so tests that add handlers don't
       effect those that depend on no handlers being registered.

That looks like the proximate cause to me; a root:WARNING log will go
to the console in the absence of other handlers.

You might be better off with a FakeLogger or similar fixture to
capture the log messages and attach them to the result (which will
allow developers to see them).

e.g., in setUp:
self.useFixture(FakeLogger())

Sadly though, fixtures.FakeLogger doesn't implement the getDetails()
method (it didn't exist IIRC, when FakeLogger was created); that
should be a small patch, which I could either do or review if you
choose to go down that path.

That said, there are three possible reasons for memcache sets to be failing:
 - tests run outside the Memcache Layer
 - the Memcache Layer config not being honoured properly
 - an actual memcache issue.

It seems entirely possible to me that the memcache side of this is
entirely unrelated to parallel testing per se and has been around for
some time.

-Rob